Background of the Invention
[0001] This invention relates to adhesive bandages comprising a surgical adhesive tape backing
on which is an absorbent pad having a perforated film-type nonadherent wound release
cover, and is more particularly concerned with such adhesive bandages in which the
wound release cover is coated with a very thin layer of a high molecular weight polyethylene
oxide to improve the hemostatic effect of such adhesive bandages when applied to minor
cuts, abrasions and puncture wounds.
[0002] Adhesive bandages having a nonadherent wound release cover in the form of a perforated
plastic film which are useful in the present invention are disclosed in U.S. Patent
3,434,472 (Smith & Nephew Ltd.) and are well-known commercially available materials,
e.g., from Johnson & Johnson as BAND-AID
* Brand Adhesive Bandages (containing a non-stick cushion pad) in the form of sheer
strips, patches, spots, plastic strips; from Colgate-Palmolive Co. (Kendall) as Curity
CURAD
* "Ouchless" Adhesive Bandages, and from American White Cross Laboratories, Inc. as
STIK-TITE
* elastic strips. Other useful perforated film type nonadherent wound release cover
surfaces suitable for use in the present invention are taught in U.S. Patent 3,285,245
(Minnesota Mining and Manufacturing Company) and in U.S. Patent 2,923,298 (The Kendall
Company). In all of these adhesive bandages, the wound release cover is very thin,
usually less than 10 mils thick.
[0003] These known adhesive bandages, are commonly applied with slight pressure to minor
cuts, abrasions and puncture wounds where they aid in stopping the bleeding, as well
as in protecting the wound from contamination. While these adhesive bandages work
reasonably well, it would be highly desirable if they could also have an improved
hemostatic effect which could be obtained conveniently, inexpensively, and in a manner
compatible with the various high-speed production techniques and equipment commonly
used to make such adhesive bandages on a commercial scale.
Summary of the Invention
[0004] Improved hemostatic adhesive bandages have been sought for many years. We have unexpectedly
found that the application of a very thin coating of polyethylene oxide having a molecular
weight above about 600,000 Daltons to the surface of the wound release cover substantially
increases the hemostatic effect when the adhesive bandage is applied to minor cuts,
abrasions and puncture wounds to stop the bleeding faster, without changing its wound
release characteristics. Comparing the hemostatic effect of a commercially-available
adhesive bandage which has a polyethylene non-woven net wound release cover surface
with a comparable adhesive bandage of the present invention which differed only in
having an approximately five percent add-on, based on the weight of the non-woven
net, of polyethylene oxide which has an approximate molecular weight of 4,000,000,
the hemostatic adhesive bandage of the present invention stopped bleeding of a minor
cut about one-third faster. Where the polyethylene oxide used has a higher molecular
weight, even less of an add-on is needed to attain a comparable hemostatic effect.
[0005] "Polyethylene oxide", which is used in the present invention, is also referred to
as poly(ethylene oxide), or as polyoxyethylene polymer or resin, or as 1,2 epoxide
polymer, or as Polyox, or by various other synonyms, and is included within the CAS
Registry Number 25322-68-3. The particular polyethylene oxides useful here are high
molecular weight polymers with average molecular weights from 600,000 and higher.
The Prior Art Distinguished
[0006] Anderson U.S. Patent 3,328,259 (assigned to Parachem Corporation) entitled "Dressing
for a Wound Containing a Hemostatic Agent" describes making a dressing for a wound
containing a hemostatic agent using a cellulose derivative, particularly the sodium
salt of carboxymethyl cellulose for that purpose. This patent says that polyoxyethylene
(Polyox) is an equivalent for the cellulose derivative specifically described, but
gives no specific details of how the Polyox is to be used. If the polyoxyethylene
were to be substituted for the cellulose derivatives described in said prior art patent,
there are a great many differences between that dressing and the hemostatic dressing
of the present invention. Thus, said prior art patent calls for a "film-like bandage"
where the film is relatively thick on the order of 1-6 mils, whereas in the present
invention the polyoxyethylene is not used in the form of a film, but rather in the
form of a very thin coating (which normally would be less than 0.1 mils), and which
coating may not even be a solid coating, but could be a porous coating since the perforated
film wound release cover substrate to which it is applied contains openings which
may not all be bridged after the polyoxyethylene is coated thereon. The prior art
film remains as a film when applied to the wound, whereas the very thin coating of
polyoxyethylene of the present invention upon application to a wet wound instantly
dissolves and no longer exists as a film but rather as a viscous solution. The prior
art film is much thicker than any reinforcing backing which it may contain, while
in the present invention the polyoxyethylene coating is much thinner than the wound
release surface, to which it is applied. The prior art thick film always contains
a plasticizer, which is not needed (but could be used) for the purposes of the present
invention. The prior art patent also is not concerned with an adhesive bandage or
with a bandage designed for use for the type of wounds to which the adhesive bandages
of the present invention will be used, but rather is concerned with a bandage used
in a different way for a different purpose, and which requires that the film from
the wound be removed from the wound by treatment with water in order not to disturb
the wound in any way, while the hemostatic adhesive bandage of the present invention
is merely pulled off in the normal manner and just does not adhere to the wound.
[0007] King, U.S. Patent No. 3,419,006, teaches a dressing utilizing a layer of a hydrophilic
polymer gel made from cross-linked poly(ethylene oxide). Such a dressing is quite
different in construction, size and operation from the adhesive bandage of the present
invention which does not utilize the cross-linked form of poly(ethylene oxide) and
does not utilize any hydrophilic polymeric gel. In fact, a commercial form of the
dressing of the King patent, available as SPENCO 2nd SKIN Dressing (Spenco Medical
Corporation) [and also as VIGILON
8 Brand Primary Wound Dressing, (C.R. Bard Inc.)], did not have as much of a hemostatic
effect when tested, as did a plain prior art type adhesive bandage control. These
dressings, which are 40 mils thick, are gels of a colloidal suspension of radiation-cross-linked
polyethylene oxide (4%) and water (96%) on a polyethylene mesh support. They are just
not applicable for use as, or in place of, the hemostatic adhesive bandages of the
present invention.
DESCRIPTION OF DRAWINGS
[0008]
Figure 1 is a plan view illustrating a hemostatic adhesive bandage of the present
invention with certain portions shown in cut-away fashion.
Figure 2 is a cross-sectional view taken along line 2-2 of Figure 1.
Figure 3 is an exploded perspective view of the adhesive bandage of Figure 1.
DETAILED DESCRIPTION OF THE INVENTION
[0009] The hemostatic adhesive bandages of the present invention comprise an adhesive bandage
of the medical or surgical type, including an adhesive strip having attached thereto
an absorbent pad bandage portion covered with a perforated plastic film non-adherent
wound release cover which wound release cover has been coated with a very thin coating
of a hemostatic agent comprising a high molecular weight polyethylene oxide.
[0010] The drawings all illustrate the same typical embodiment of the hemostatic adhesive
bandage 10, in which the adhesive coated backing 12 has affixed to it an absorbent
pad structure 20 having an absorbent pad 22 covered by a perforated film-type non-adherent
wound release cover 24 which is coated with a very thin coating of a high molecular
weight polyethylene oxide 26. The polyethylene oxide coating 26 may or may not have
openings corresponding to those on the release cover 24.
[0011] Not shown, but which will normally be utilized in actual use, are two strips of release
paper (such as a silicone- coated release paper or other alternate materials which
can be readily removed at the time of use), which are applied so as to cover, in an
overlaying manner, the entire adhesive side of the hemostatic adhesive bandage. Also
not shown, but which will be normally used, is an individual sealed package made of
glassine-paper or a similar bacterial barrier material into which each hemostatic
adhesive bandage is placed before it undergoes ethylene oxide sterilization so as
to maintain sterility until the adhesive bandage is ready for use. At that time, the
user would open the sterile package, remove the hemostatic adhesive bandage, remove
the two strips of release paper and apply the polyethylene oxide coating 26 side of
the absorbent pad structure 20 to the wound and then the adhesive end portions to
the skin to hold the entire structure in place.
[0012] The distinction between prior art adhesive bandages and the hemostatic adhesive bandage
of the present invention is in the added presence of the polyethylene oxide coating
26. Thus, the usual prior art methods of manufacture applicable to the prior art adhesive
bandages and to the various materials and ingredients used therein may be used here
also, except that irradiation sterilization, e.g., with Cobalt 60, should not be used
since it will crosslink the polyethylene oxide and render it non-hemostatic. Steam
sterilization should not be used either. Instead, the widely used ethylene oxide method
of sterilization can be used.
[0013] While the drawings illustrate one shape, the hemostatic adhesive bandages may take
any shape in which the prior art non-hemostatic adhesive bandages may be made.
[0014] The adhesive backing 12, may be made from any cloth or plastic type fabric coated
with any pressure-sensitive adhesive which is customarily used on the prior art non-hemostatic
adhesive bandages.
The Polyethylene Oxide
[0015] The present invention requires the use of polyethylene oxide as a thin coating for
a perforated plastic film wound release surface, for the preparation of a hemostatic
adhesive bandage. We have found, unexpectedly, that very small quantities of polyethylene
oxide are very effective in reducing the bleeding time of minor wounds, the polyethylene
oxide being employed as a very thin coating on a porous plastic substrate, i.e., on
the release pad of an adhesive bandage.
[0016] The polyethylene oxide resins useful for the present invention are not crosslinked
to form a gel as occurs when the polyethylene oxide is irradiated. It should be understood
that the term "polyethylene oxide", when used in describing and claiming the present
invention, refers only to the non-irradiated, non-crosslinked, non-gel forms thereof.
[0017] Polyethylene oxide resins are made commercially by the catalytic polymerization of
ethylene oxide in the presence of any one of several different metallic catalyst systems.
They are currently available [from Union Carbide Corporation (U.S.) as "Polyox", from
Meisei Chemical Works Ltd. (Japan) as "Alkox" and from Seitetsu Kagaku Co. Ltd. (Japan)
as "PEO"] with average molecular weights from as low as 200 to up to 7 million. However,
those products with a molecular weight below 25,000 are viscous liquids or waxy solids,
commonly referred to as polyethylene glycols. The polyethylene oxide resins which
are useful for the present invention have a molecular weight range from 600,000 to
7,000,000, and even higher, should such materials later become available. They are
dry, free flowing, white powders completely soluble in water at temperatures up to
98°C and completely soluble in certain organic solvents. They have crystalline melting
points from 63° to 67°C. Above the crystalline melting point the resins become thermoplastic
materials which can be formed by molding, extrusion or calendering. Aqueous solutions
display increasing pseudoplasticity and pituitousness as the molecular weight of the
resin increases.
[0018] Because the paired ether-oxygen electrons in these polymers have a strong affinity
for hydrogen bonding, polyethylene oxide resins form association complexes with a
wide variety of monomeric and polymeric organic compounds as well as certain inorganic
electrolytes.
[0019] Thus, for example, polyethylene oxide forms association compounds with proteins such
as gelatin, polyureas and organic compounds like urea and thiourea.
[0020] While we do not wish to be bound by any particular theory of how our invention works,
it is postulated that the combination of the very high viscosity that small amounts
of polyethylene oxide can impart to water along with its ability to form association
compounds with certain proteins, is responsible for the hemostatic property of these
polymers. We speculate that when an adhesive bandage containing a small amount of
polyethylene oxide resin is placed on a bleeding surface the resin rapidly dissolves
in the aqueous plasma of the blood and thereby immediately increases the viscosity
of the plasma. At the same time, blood proteins, such as prothrombin and fibrinogen,
begin to associate with the polyethylene oxide molecules thus increasing the local
concentration of these proteins and effecting more rapid interaction among them, compared
to the normal diffusion controlled reactions in the absence of the polyethylene oxide.
Thus, the increase in viscosity of the plasma which slows the flowing blood and the
concentrating of the essential blood proteins at the surface of the polyethylene oxide
molecules are postulated to be the mechanism for the hemostatic efficacy of polyethylene
oxide.
[0021] In order for the polyethylene oxide molecules to bring about quick hemostasis we
have found it necessary for the polymer to rapidly dissolve in the plasma of the blood
issuing forth from the cut or wound site. This is achieved readily if the polyethylene
oxide is in the form of a very thin film coating on the surface of the adhesive bandage.
The polyethylene oxide thin coating could be on either surface of the release cover,
but preferably is on the side of the surface closest to the wound.
[0022] While the polyethylene oxide is the key hemostatic material, other water-soluble
polymers may be added to the polyethylene oxide without appreciably diminishing the
hemostatic activity of the polyethylene oxide, and such mixtures are to be regarded
as the full equivalents of the polyethylene oxide itself for purposes of the present
invention, the other added water-soluble polymer or polymers being merely a diluent.
In any such mixture, the major component preferably should be the polyethylene oxide,
but there could be present up to 50 weight percent [based on the weight of all the
polymers, including the polyethylene oxide] of one or more other water-soluble polymers.
Good demonstrated results have been obtained with mixtures of polyethylene oxide and
sodium carboxymethyl cellulose (50:50) and mixtures of polyethylene oxide and polyvinyl
pyrrolidone (50:50). Representative of the many other water-soluble polymers useful
for this purpose are the alkyl celluloses, hydroxyalkyl celluloses, polyvinyl alcohol,
polyacrylamide aad partially hydrolyzed polyacrylamides, and various naturally-occurring
gums such as guar, alginates, xanthan and similar materials.
[0023] Also, while the use of plasticizers with the polyethylene oxide is not preferred
or necessary for purposes of the present invention, water-soluble plasticizers, such
as glycerine, polyethylene glycol and the like, optionally may be added if desired.
[0024] Where it is desired to include another water-soluble polymer or polymers and/or a
water-soluble plasticizer, this can be done by adding these water-soluble materials
to the polyethylene oxide solution before it is coated onto the wound release surface.
[0025] We have found that the use of the above water-soluble polymers and water-soluble
plasticizers as diluents does not significantly adversely affect the hemostatic activity
of the polyethylene oxide. The properties of the very thin coating placed on the release
cover remain about the same as with polyethylene oxide alone, and the material still
processes well on high speed adhesive bandage making equipment.
The Wound Release Surface
[0026] Many known commercially produced adhesive bandages contain a thin perforated plastic
film atop the absorbent pad. The plastic film functions as a wound release cover surface
so that when the bandage is removed the scab will not be disrupted and reinitiate
bleeding.
[0027] This wound release cover can be made of a plastic material, of which the most commonly
encountered examples are polyethylene, polypropylene, polyesters and nylon. The plastic
film is perforated in different ways which all serve to provide small openings for
the blood to enter the absorbent pad beneath the perforated film. This plastic release
surface can also be a woven, knitted, or non-woven structure, so long as it contains
apertures sufficient to permit the blood to flow into the absorbent pad. Representative
examples include materials such as Delnet film of polyethylene and Telfa film of polyester.
[0028] Illustrative of various preferred non-adherent wound release covers are those available
from Hercules as one of their series of Delnet light weight, non-woven fabrics made
from high-density polyethylene or polypropylene through a process of extrusion, embossing
and orientation. These have weights of about 0.36-1.06 oz/yd
2, a thickness of about 4-10.5 mils, and an open area of 17-46%. In particular, we
prefer to use Delnet P-530, which is a high density polyethylene of a weight of 0.55
oz/yd
2 a thickness of 4.3 mils and an open area of 34%, and which material was utilized
in those examples where no other material was specified.
The Coating Operation
[0029] We have found, as part of this invention, that coating the wound release cover with
a very thin coating of polyethylene oxide (much thinner then the release cover) is
a very effective method for getting the polyethylene oxide to the bleeding site.
[0030] It makes no difference whether the perforated plastic release cover is coated first
and then attached to the absorbent pad of the bandage or if the release film is first
attached to the absorbent pad (as in a unitized pad) and the whole entity is then
coated with a polyethylene oxide solution to produce a thin coating or film on the
release film.
[0031] During the coating operation, some or all of the perforated holes in the plastic
release cover may be bridged with a thin coating of polyethylene oxide. Since the
coating or film is so thin «0.1 mils) it dissolves immediately upon becoming wetted
with plasma from the blood. Thus the perforated holes are not blocked by this hemostatic
polymeric coating or film.
[0032] In order to coat the release cover with polyethylene oxide, the polyethylene oxide
polymers found effective in this invention [which range in molecular weight from 600,000
to 7 million or higher if available], are solubilized by dissolving them in various
solvents or mixtures of solvents.
[0033] The concentration of the polymer in the solvent can range from a low of 0.5% to a
high of 6.5%, but most preferred are 2.0% to 3.0% for polyethylene oxide having a
M.W. of 4,000,000 and 1.0% to 2.0% for polyethylene oxide having a M.W. of 7,000,000.
Typical of the various solvents which may be used are water, water-methyl alcohol
mixtures, isopropyl alcohol, benzene, acetone and methylene dichloride, but the possible
solvents are not limited to those mentioned above.
[0034] Alternatively, since polyethylene oxide is a low temperature melting thermoplastic
polymer, it can also be extruded as a melt into a thin film directly onto the absorbent
pad or the release film.
[0035] Our preferred method is the solvent coating of the polyethylene oxide polymer directly
on the wound release cover or directly onto the absorbent pad where the nature of
the absorbent pad is such that it does not require a separate wound release cover
because the wound release cover previously was built into the absorbent pad structure
itself, i.e., a unitized pad.
[0036] The coating operation to apply the polyethylene oxide is conducted most preferably
with a reverse roll coater. The type of coater is not a part of this invention and
is only mentioned as an example of one type of coating technology that has been put
into practice. Many types of coating technology and equipment are applicable for use
in making the hemostatic bandages of this invention.
[0037] More important than the type of coater is the amount of high molecular weight polyethylene
oxide applied to the adhesive bandage. We have found that an increase in weight of
the porous polymeric wound release cover of 1-10% is sufficient to produce a significant
hemostatic effect.
[0038] The most preferred add-on increase is 3-8% for the 4,000,000 M.W. polyethylene oxide,
and 2-6% for the 7,000,000 M.W. polyethylene oxide of the original weight of our Delnet
polyethylene wound release film. These add-on amounts are so small that they are difficult
to detect with the naked eye.
[0039] The hemostatic adhesive bandages of the present invention are made using the same
high-speed production techniques and equipment as are used for commercially available
non-hemostatic adhesive bandages. Since the inventive feature is in the polyethylene
oxide coating on the wound release cover, the Examples below illustrate that aspect
of the invention.
Example 1:
[0040] Into a large pail add 29.28 kilograms of isopropyl alcohol. While stirring rapidly,
add 0.90 kilograms of polyethylene oxide (Union Carbide's Polyox Resin WSR-301, molecular
weight 4,000,000). The polymer disperses in the alcohol but does not dissolve. Add
5.82 kilograms of distilled water and stir slowly for 15 minutes. The polyethylene
oxide rapidly dissolves as the water is added. This procedure produces a 2.5% Polyox
solution concentration with a Brookfield viscosity of 15,433 cps using spindle No.
1 at 1 rpm. The solution is 81.33% by weight in isopropyl alcohol and 16.16% by weight
in water.
[0041] This solution is coated onto a net-like perforated polyethylene film known as Delnet
P-530 produced by Hercules, Inc. The Polyox solution is coated onto the Delnet with
a reverse roll coater. After the Delnet is coated with a thin film of the Polyox solution,
the coated Delnet film passes through warm ovens to evaporate off the solvents leaving
a very light film of polyethylene oxide coated on the Delnet film which is then rolled
up. The weight increase of the Delnet was 8.1%.
[0042] The coated Delnet roll is attached to an absorbent pad made of wood pulp, which is
then cut and attached to an adhesive-coated backing, all by high speed machinery well-known
to those skilled in the art of making adhesive bandages. The coated Delnet P-530 processes
through the machinery with no problems and produces hemostatic adhesive bandages that
are virtually indistinguishable from regular bandages in every aspect, except for
the bleeding time measured on a cut. Thus, for example, adhesive bandages made by
the process of this example exhibited, an average bleeding time on rabbit ear cuts
(a model for human cuts) of 49 seconds versus a control of 83 seconds. (The control
is an identical adhesive bandage but uncoated with Polyox).
Example 2
[0043] Into a large bucket charge 1,187.5 grams methyl alcohol. with rapid stirring add
125 grams of polyethylene oxide (Union Carbide Polyox Resin WSR-205, molecular weight
600,000). The polyethylene oxide disperses but does not dissolve. Add 1,187.5 grams
distilled water and reduce the stirring speed as the polymer dissolves and the viscosity
increases after 20 minutes of stirring. The 5% solution of Polyox resin WSR-205 in
47.5% methyl alcohol, 47.5% water is ready for coating. This solution exhibits a Brookfield
viscosity of 5701 cps using a No. 1 spindle at 1 rpm.
[0044] This resin is coated onto Delnet P-530 film in a manner described in Example 1. A
very thin film of polyethylene oxide is layed down by this process on the perforated
Delnet polyethylene film. The uncoated Delnet P-530 film has a weight of 0.450 oz.
per square yard. The Polyox add-on was 0.027 oz. per square yard or a 6% increase
over original weight.
[0045] This coated Delnet film is manufactured into adhesive bandages by machinery which,
at high speeds, attaches the coated Delnet to the absorbent pad which comprises the
bandage. The machinery used is the same high speed commercial equipment used to make
the prior art non-hemostatic adhesive bandages. The bandages are sterilized with ethylene
oxide with no damage to the hemostatic coating. When the above bandages were tested
on a rabbit ear bleeding model, the average bleeding time for the hemostatic bandage
was 60 seconds versus 86 seconds for the uncoated control.
Example 3
[0046] This example illustrates the application of polyethylene oxide resin to a unitized
pad. This unitized pad is one in which the porous plastic film or release cover surface
is prebonded to the absorbent pad which is a composite of 90% polypropylene, 10% rayon.
Thus, the Delnet P-530 film is prebonded to the 90/10 pad and the polyethylene oxide
resin is coated directly onto the surface of this material.
[0047] A 2.0% solution of Polyox WSR-301 (molecular weight 4,000,000) is prepared in a mixed
solvent of 58.8% methyl alcohol, 39.2% water. This solution has a viscosity of 8,552
centipose using a Brookfield viscometer with a No. 1 spindle at 1 rpm.
[0048] The solution of polyethylene oxide (Polyox WSR-301) is coated onto the unitized pad
with a reverse roll coater. A thin film of polyethylene oxide forms on the surface
of the Delnet bonded to the 90/10 absorbent pad. The unitized pad weighs 3.145 oz.
per sq. yard. The coated pad weighs 3.172 per sq. yard, or a pick up of 0.027 oz.
per sq. yard, or 0.85% increase based on entire pad, or 6% increase based on the Delnet
film only. This material is converted into adhesive bandages by well known commercially
available equipment and technology normally used for non-hemostatic adhesive bandages.
When these bandages were tested on a bleeding rabbit ear model they exhibited a bleeding
time average of 48 seconds for the hemostatic bandage versus 72 seconds for the uncoated
control with a standard deviation of 17.
Example 4
[0049] A 2% solution of Polyox WSRN-60K (molecular weight 2,000,000) is prepared in a mixed
solvent consisting of 58.8% by weight water and 39.2% by weight methyl alcohol. This
solution exhibits a Brookfield viscosity of 4,030 cps with a No. 1 spindle at 1 rpm.
[0050] This solution is coated onto a Delnet perforated polyethylene film and then passed
through an oven to evaporate the solvents. The weight add-on to the Delnet is 8.0%.
The thickness of this film is less than 0.1 mils. The coated Delnet is manufactured
into adhesive bandages by high speed machinery which attaches the Delnet to an absorbent
pad. These bandages, when tested for bleeding times, stopped bleeding faster by 40%
in the time compared to an uncoated control.
Example 5
[0051] This example illustrates the effect of polyethylene oxide on a polyester perforated
film called Telfa [which is used commercially on bandages available from Colgate-Palmolive
as Curity Telfa adhesive pads].
[0052] A 2.0% by weight of Polyox WSR-301 in a solution of 58.8% methyl alcohol, 39.2% water
was coated onto a perforated polyester film called Telfa with the help of a draw knife.
A very thin film, .1 mil, of polyethylene oxide was laid down on the polyester surface.
The coated Telfa film was placed over an absorbent pad and this makeshift bandage
was tested on the bleeding ear of a rabbit. The bleeding times of this hemostatic
bandage were 30% shorter than an otherwise identical but uncoated control.
Example 6
[0053] Into a large pail is added 1,773 grams methyl alcohol. While stirring add 45 grams
Polyox WSR-303, mol. wt. 7 million. The Polyox Resin does not dissolve but disperses
in the methanol. While stirring add 1,182 grams of water and stir for 1 hour. This
procedure produces a 1.5% Polyox solution in 39.4% water, 59.1% methyl alcohol. The
viscosity of this solution is 11,100 cps measured on a Brookfield viscometer using
Spindle No. 1 at one rpm.
[0054] This solution is coated onto Delnet P-530 with a reverse roll coater. The coated
Delnet passes through a warm oven to evaporate off the solvent. The weight percent
increase of the Delnet is 3.5%.
[0055] The coated Delnet roll is attached to an absorbent pad made of wood pulp, and made
into adhesive bandages. These bandages, when tested for hemostasis, stop bleeding
on a rabbit ear model in 52 seconds versus a control of 85 seconds.
Example 7
[0056] Into a large pail add 1,746 grams methyl alcohol and 60 grams Polyox WSR-301. Into
another pail dissolve 30 grams of sodium carboxymethyl cellulose #7H3SCF from Hercules
Incorporated in 1,164 grams water. Stir this solution for 2 hours, then add the aqueous
polymer solution to the - stirring suspension of Polyox in methyl alcohol. Stir the
resulting solution for 2 hours. This polymer solution exhibits a Brookfield viscosity
of 64,000 cps; and consists of 2.0% Polyox WSR-301, 1.0% CMC, 38.8% water and 58.2%
methyl alcohol.
[0057] This solution is coated onto Delnet and the solvent evaporated off in a warm oven.
The percent add on is 7.5%.
[0058] When this coated Delnet is made into adhesive bandages, these bandages exhibit a
bleeding time of 50 seconds compared to a control of 80 seconds.
Example 8
[0059] Into a large pail, add 1,746 grams methyl alcohol. To this with stirring add 40 grams
of Polyvinylpyrrolidone K-90 from GAF Corporation. Stir this solution until the PVP
is dissolved. Add to this solution 40 grams of Polyox WSR-301 and while stirring add
1,104 grams water. Continue stirring for 1 hour. This procedure produces a polymer
solution with a concentration of 1.36% in PVP, 1.36% in Polyox, 59.6% in methyl alcohol
and 37.7% in water.
[0060] The viscosity of this solution is 8,800 cps measured with a Brookfield viscometer
using Spindle No. 1 at one rpm.
[0061] This solution is coated onto Delnet and the solvent evaporated off in a warm oven.
The weight percent increase to the Delnet is 5.0%. This coated Delnet is made into
adhesive bandages as previously described. When tested for hemostasis, these bandages
stop bleeding on a rabbit ear model in 58 seconds, versus a control of 83 seconds.
Example 9
[0062] Into a large pail equipped with a stirrer add 1,176 grams methyl alcohol. While stirring
add 40 grams of Polyox coagulant grade mol. wt. 5 million. Stir for a few minutes,
then add 784 grams water and stir for 1 hour. This procedure produced a 2.0% solution
of coagulant grade Polyox in 58.8% methyl alcohol and 39.2% water.
[0063] This solution exhibits a Brookfield viscosity of 7,300 cps using a Number 1 Spindle
at one rpm. This solution is coated onto Delnet using a reverse roll coater and the
solvent evaporated off in a warm oven. The add on to the Delnet is 6.0%. When the
coated Delnet is manufactured into adhesive bandages, these bandages exhibit a bleeding
time of 53 seconds versus 85 seconds for the control when tested on a rabbit ear model.
TEST PROCEDURE FOR HEMOSTASIS
[0064] The hemostasis effect of the dressings of the present invention (as shown in the
preceding Examples 1-5) was evaluated by the following rabbit ear hemostasis test
which simulates, in a laboratory, the type of minor cuts that adhesive bandages are
often used on.
[0065] The test procedure is as follows:
1. Inject each rabbit I.M. with "Rabbit Magic" anesthetic at a dosage of lcc per 5
lbs of body weight. The "Rabbit Magic" must be made fresh daily:
1 cc ROMPUN (20 mg/ml)
2 cc Ketamine Hydrochloride (100 mg/ml)
1 cc Saline or H20
2. Shave the medial marginal vein on both ears. Place ear on a hard, flat surface
and make an incision with a razor blade across the entire width of the vein, being
careful not to completely transect the vein. Be sure the segment of vein selected
is of consistent and fairly large diameter.
3. Wipe the first bit of blood off the incision with a gauze sponge and observe the
wound site for adequate, but not profuse, blood flow. Wipe the incision once again
with a gauze sponge and immediately cover the incision with an adhesive bandage sample
(clear or sheer backing) perpendicular to the vein and simultaneously start a stopwatch.
Hold thumb on the sample over the wound site with slight pressure for 5 seconds to
assure adequate contact between sample and incision.
4. When all visible bleeding has stopped, record the time in seconds for the hemostatic
time. If sample saturates before hemostasis occurs, discard sample, record as saturated
and repeat Steps 2 and 3 with a new sample.
5. Make a second incision on the same ear within the originally chosen segment and
test as above. Make 2 to 3 incisions per ear, alternating samples in a random fashion.
[0066] Using the above procedures adhesive bandages of the invention were tested and their
hemostatic effect (i.e., the number of seconds for visible bleeding to stop) was recorded
in Table I.
[0067] In order to carry out the above test procedure for hemostasis, it is necesary to
look through the backing of the particular adhesive bandage which is being tested
in order to observe the blood flow, i.e., to tell when bleeding has stopped. Because
some types of commercially available adhesive bandages have backings which are opaque
and not transparent, and come in different sizes and shapes, they were modified for
test purposes. This was done by using the same Delnet covered absorbent pads as are
used commercially, but where necessary combining them with a different, albeit still
commercially used, adhesive backing, and forming them into a 3/4 inch size adhesive
bandage using the normal high-speed production techniques and equipment, even if that
is not their customary size. Thus a "sheer vinyl backing" or a "tricot" backing was
always used as the adhesive backing for test purposes. These backings were used with
three different pads, i.e., with the 4-fold pads used commercially in BAND-AID
* Brand Vinyl Adhesive Bandages (made from wood pulp and rayon) (Pad A); with the pads
used in BAND-AID
* Brand vinyl backed spots and juniors (a unitized pad made from 100% rayon) (Pad B);
and with the pads used in BAND-AID
* Brand flexible fabric adhesive bandage tricot mesh (a unitized pad made from 90%
polypropylene-10% rayon) (Pad C). All the pads had a Delnet P-530 perforated polyethylene
film wound release cover.
[0068] Various runs were made to obtain the hemostatic adhesive bandages (which contained
an approximate 7% target add-on of Polyox Resin WSR-301), which adhesive bandages
were then tested against identical non-Polyox containing adhesive bandage as a control.
Usually 12 adhesive bandages from each production run were used in each test. Using
pooled data (from some 40-106 samples tested for each of Pads A, B and C) the following
results were obtained:
RABBIT EAR HOMOSTASIS TEST
[0069]
![](https://data.epo.org/publication-server/image?imagePath=1987/01/DOC/EPNWA2/EP86304576NWA2/imgb0001)
The hemostatis effect of the dressings of Examples 6-9 was evaluated by the same general
procedures described above. As is apparent, the hemostatic adhesive bandage of the
present invention has a statistically significant hemostatic effect.